Iron ore concentrate, finely divided iron ore in powder form, from which undesired components of the ore have been removed, is mixed with water in a preparation plant in order subsequently to be processed in a pelletising plant is known.
The ore concentrate is dewatered in the pelletising plant and mixed with various additives and binding agents, and rolled to small pellets. The pellets are dried in a drying arrangement and heated in a compartment such that the pellets are oxidised and sintered, caused to melt together, one by one, to form final pellets, which maintain their shape during further transport. A cooling of the pellets subsequently takes pace in a cooling arrangement. The pellets are now ready and can be transported onwards to the locations at which the ore is to be further refined.
The use of an arrangement comprising an inlet connected to the compartment for introduction of a medium through the inlet and into the compartment is previously known. A combustion arrangement is arranged in the inlet for heating the medium. The combustion arrangement comprises fuel that, when the arrangement is in use, is ignited and combusted. Combustion heat is developed during the combustion of the fuel, which heat is transferred to the medium that is present at the combustion arrangement in the inlet and that passes through the inlet on its way to the compartment.
The heating of the pellets in a compartment is a very critical step in the processing of the pellets and requires a relatively high temperature in order to obtain a good result, in order for the pellets to be durable.